There is a feeling among overseas charities that more could have been done earlier, which would also have lowered costs.
The Disasters Emergency Committee (DEC) started transmitting TV and radio messages yesterday, following last week's decision to launch an appeal.
"The whole sector is feeling bad that it has got to this stage, but now it is time to act as fast as possible," said Gareth Owen, deputy director of emergencies at Save the Children.
Oxfam called on international governments to work together to prevent delays occurring in future. It estimated that the crisis will cost £46 per starving person, whereas it would have been only 60p six months ago.
Phil Bloomer, director of campaigns and policy at Oxfam, said that world leaders had not done enough. "It is outrageous that the world waits until children are dying before acting to save them," he said. "It wasn't until international TV crews arrived last week that money really started coming in."
The crisis in West Africa, including Niger and Mali, was first highlighted last November. Today about eight million people are at risk of starvation after the combination of drought and plagues of locusts obliterated most of the area's agricultural production.
Paul Anticoni, head of international aid at the British Red Cross, said the DEC campaign was launch-ed to highlight the severity of the crisis and counteract any fundraising competition between agencies.
However, some agencies that are not members of the DEC are concerned that their fundraising activities will be affected. Victor Bull, director of operations at Christian Hope International, said: "I don't believe the DEC has taken into consideration the effect it has on other UK charities."
Debra Allcock Tyler of the Directory of Social Change said the DEC's second appeal within eight months placed a responsibility on firms and governments to ensure less publicised causes were not forgotten.
RED CROSS BLOGGER
A journalist at the British Red Cross has been writing a weblog on the BBC news web site to keep supporters up to date with the current situation in west Africa. This is the first time the charity has sent a journalist out with an emergency response unit tasked with writing a blog on his experiences and supplying copy to international news agencies. Mark Snelling's online diary aims to show supporters how the charity "is making a difference".